The invention concerns a security element for RF identification and a security document, in particular a passport having such a security element.
U.S. Pat. No. 4,220,956 describes an RF identification circuit (RF=radio frequency) which has an array of antennae which are produced by means of an etching process from a copper laminate. The copper laminate is applied to a dielectric. As the dielectric does not afford any electrical functions, it can be of a very thin configuration whereby the mechanical to flexibility of the RF identification circuit is increased.
U.S. Pat. No. 5,528,222 describes an RF identification circuit which reflects an RF carrier sent by a base station back to the base station and in so doing modulates on to the reflected signal additional information in accordance with a pre-programmed information protocol. The RF identification circuit has a semiconductor circuit with a memory and one or more RF components of an RF circuit. The semiconductor circuit is mounted on a substrate. The RF signal received by the antenna is forwarded to the semiconductor circuit. The substrate is a flexible, non-conducting substrate. The antenna is an integral component part of the substrate. It comprises a track with is between 25 and 35μm thick and which is applied to a polyester or polyamide layer.
By virtue of that structure the RF identification circuit is of a very thin and mechanically flexible form.